Electric heater



April 30, 1940. B RNES 2,198,694

, ELECTRIC HEATER Filed Ju1y 8, 1938 2 Sheets-Sheet l INVENTOR. VV/LL/AM A, EAR/v56 WWW Patented Apr. 30, 1940 UNITED STATES 2,198,694 ELECTRIC HEATER William A. Barnes, Mansfield, Ohio, assignor to Dominion Electrical Manufacturing, Inc., a corporation of Ohio Application July 8, 1938,,Serial No. 218,043

. 1 Claim.

My invention relates, in general, to an electric heater and a method of constructing same of light weight metal.

An object of my invention is to provide a cheap flector casing with very few screws or bolts thereby eliminating much hand work.

. Another object of my invention is to provide a rigid double-Walled cabinet structure of very light metal.

Another object of my invention is to reduce die costs by using the same die to shape the front and back parts of the casing.

Still another object of my invention is to furnish a simple and easy method of assembling a heater made of light metal.

Another object of my invention is to furnish a heater in which no fastening means are'vlsible on the outside.

Another object of my invention is to use several of the structural members for more than one purpose thereby eliminating a number of the parts which were heretofore necessary.

Another object of my invention is to construct an electric heater using metal tabs to fasten the various parts together instead of the usual nuts and bolts.

Other objects and a fuller understanding of my invention may be had by referring to the following description and claim, taken in conjunction with the accompanying drawings, in which:

Figure -1 is a partially cut away isometric view of my heater without the top showing the relative positions of the assembled parts;

Figure 2 is an isometric View of my heater completely assembled and shows the preferred assembly of the heating element;

Figure 3 represents a front view of'the outer forward portion of my heater showing the grill opening, vents, parts of the side wall and the tabs just as they would appear after the blanking die stamping operations have been finished and before it is formed;

Figure 4 shows the outer rearward portion of my heater showing the side walls and the tabs after theblanking die stamping operations have been finished and before it is formed;

Figure 5 shows the integral back and side in ternal reflecting walls after the blanking die stamping operation has been finished and before it is formed;

Figures 6 and 7 show the top and bottom lateral bracing means before the ends have been turned up;

Figure 8 shows the front reflecting portion after the die stamping operation and before the forming operation which turns up the ends; and

Figure 9 shows the insulator hook support after the die stamping operation.

In the sale of portable electric heaters, there are many important factors beside the heat producing qualities which affect the sale of the product. Among them are the cost, durability, ap pearance, and the weight. With this in mind, I designed a heater to be made from thin metal and with few parts. It was necessary, therefore, to devise some novel method of putting it to.- gether as the requirement of rigidity would cause, under old assembly methods, numerous nuts and bolts and screws to be used.

My invention comprises a double-walled electric heater composed of an outer enclosing portion which is keptcool by a reflecting portion 59 disposed inwardly of the said outer portion. To facilitate assembly the outer enclosing portion is divided vertically substantially through the middle of the sides into an outer rearward portion 52, seen in blank form in Figure 4, and an outer forward portion 5I, seen in blank form in Figure 3. The two portions 5| and 52 are fastened to gether by the foldable tabs I6. The two outer portions 5I and 52 are substantially similar in outline and may therefore be blanked out by the same die to reduce manufacturing costs. The outer forward portion 5I is formed to provide left and right side parts I I and I2. The left side part I I is formed from the outer forward portion 5I by bending the outer forward portion substantially 90 degrees along the construction line I3 and the right side part I2 is formed by'bending the outer forward portion 5| substantially 90 degrees along the construction line I4 thereby leaving a front part II] positioned between the sides II and I2.

As my heater works on the chimney effect of taking in cool air at the bottom and letting the heated air out at a higher point, I have provided vents I5 near the bottom of the front portion Ill and a grill opening near the top in the outer forward portion 5I to facilitate the flow of air through the heater. The grill opening is cut in the said outer forward portion 5| during the stamping operation leaving foldable grill tabs 48 on the edges of said grill opening. A wire grill 50 is provided and secured in the grill opening by folding the foldable grill tabs 48 over the top and bottom wires of the grill 50.

The outer rearward portion 52 is also formed to provide left and right side parts l8 and |9. The left side part I8 is formed from the outer rearward portion 52 by bending the rearward portion 52 substantially 90 degrees along the construction line 20 and the right side part I!) by bending the rearward portion substantially 90 degrees along the construction line 2| thereby leaving a back part |1 between the sides l8 and |9.

The foldable tabs I6 are also adapted to clamp the reflecting portion 59. The reflecting portion 59 may be blanked out by a stamping operation which cuts it along line from point 53 to point 54 and along line 26 from point 55 to point 56 and formed by a subsequent operation which bends the reflector substantially 90 degrees along the construction lines 21 and 28 from points 51 and 58 to points 53 and 54 respectively to form a left side reflector 23 and a right side reflector 24, and leaving a back reflector 22 positioned between the left arid right side reflectors. Further bends 29 and 30 are put in the side reflector portions during the subsequent forming operations. These bends are located along the construction lines 29 and 39 near the top and bottom ends of each of the side reflectors 23 and 24 and are of such adegree that the top and bottom ends of the side reflectors are flush against the inside portions 5| and 52. By bending the top and bottom ends of the side reflectors outwardly, the main body portion of the reflector is spaced from the outside portions 5| and 52 to keep the outside portions relatively cool. To provide a top inclined reflector, I bend the back reflecting portion 22 forward along the double construction lines 32 and 33 and to provide a bottom reflector to reflect the heat upwards, I bend the back reflector 22 along the construction line 34. During the blanking operation the left and right side reflectors 23 and 24 are provided with tab slots 3| located in those portions of the reflectors which fit flush against the portions 5| and 52 and disposed to receive the foldable tabs I6 during assembly. The back reflector 22 is stamped with a plurality of insulator hook slots 35. These insulator hook slots 35 are adapted to receive and retain insulator hooks 45, shoulders being provided on said insulator hooks to prevent their falling through the said insulator hook slots 35.

Enclosed within the outer portions 5| and 52 of the heater are two substantially identical lateral cross-braces 38 which are die stamped by the same die to reduce manufacturing costs. The lateral cross-braces are slotted near their ends to provide tab slots 4| which are adapted to receive the tab-s I6 after the said tabs have been inserted through the tab slots 3| in the reflector portion sides 23 and 24. The cross-braces also have holes 40 stamped therethrough to permit the assembly man to insert tools through the cross-braces to facilitate folding the tabs l5 over and pressing them against the ends of the crossbraces, after the said tabs have been inserted through the reflector portions 23 and 24 to clamp the assembly rigid. It is necessary, however, before the tabs It can be inserted through the tab slots 4|, to bend the cross-braces 38 substantially 90 degrees along the construction line 43 at each end of the braces. This causes flat surfaces containing the tab slots 4| to be pressed against the ends of the side reflecting portions 23 and 24 which in turn are pressed against the portions 5| and 52. As the metal tabs |6 originate at the edges of the outer portions 5| and 52 and are inserted through the tab slots 3| in the reflecting portions 23 and 24 and through the tab slots 4| in the cross-braces 38 before they are bent over and firmly pressed against the cross-braces, they rigidly hold the heater together.

To add rigidity to the lateral cross-braces 38 by increasing the depth thereof a raised portion 42 is provided. Also provided in the cross-braces 38 are holes 39 adapted to receive and threadably engage fastening means 69 used to hold an outer top portion 46. Although both the upper crossbrace and the lower cross-brace are provided with holes 39, only the upper brace utilizes them.

To complete the internal reflecting unit, a front reflector 44 is attached to the side reflectors 23 and 24 by screws 63 inserted through holes 5| provided therefor. To enable the front re fleeting portion 44 to be engaged by the screws 63 inserted through the holes 6| in the side reflectors 23 and 24, the front reflecting portion 44 is bent substantially 90 degrees along the construction line 69 so that end portions 10 are formed containing the holes 6| to fit flush against the side reflectors 23 and 24. To increase the amount of heat which is reflected upward by the back reflector 22, I bend the front reflector 44 along the construction line 52.

An insulator hook support 49 is also provided by a die stamping operation to enable a plurality of the insulator hooks 45 to be mounted easily in the forward part of the heater. This is done by attaching the hook support 49 containing insulator hook slots 35 to the side reflectors 23 and 24 in the same manner that the front reflecting portion 24 is attached. In the hook support 49 are provided holes 66 into which attaching means 61 threadably engage after they are passed through the holes 96 in the side reflectors 23 and 24. The hook support 49 is bent along lines 11 toform end portions 15 which lie fiat against the side reflectors 23 and 24 and thereby enable the attaching means 61 to be inserted through the holes 66 provided therefor. The hook support 49 as shown in Figure 9 has been bent along the lines 1|, 12, and 13 to form an elongated tent-like structure with the line 1| as the ridge pole but with solid faces between the lines 12 and 13.

A heating element 41 originating at an inlet I terminal 35 and adapted to be suspended over the various insulator hooks 45 and terminating at an outlet terminal 31 is next provided. The heating element 41 may be a single piece of coiled wire of suitable resisting qualities.

Next the top cover portion 46, which is adapted to fit outside of the outer casing portion 5| and 52, is arranged to be secured to the heater by the top fastening means inserted through the cover portion 45 and threadably engaging the holes 39 in the top lateral cross-brace 38.

It may be seen from the foregoing description that assembling my heater is a relatively easy procedure and that it produces a heater that is light in weight yet substantial and rigid.

The smooth outside appearance and the absence of projecting fastening means is the result of using tabs H5 and having them fasten the inner reflecting walls and the cross-braces on the inside of the heater.

Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes 7 2,19a,co4

in the details of construction and the combination and arrangement of parts may be resorted to without departing from the soirit and the scope of the invention as hereinafter claimed.

I claim as my invention:

An electric air heater comprising, in combination, an outer rearward casing portion having turned side portions with foldable tabs thereon, an outer forward casing portion having an opening for heated air to pass out and having turned side portions with foldable tabs thereon, an. inner reflecting casing portion located within said outer rearward and forward casing portions and comprising integral top, side and back portions, a front inner reflecting casing portion positioned within the outer casing portions and below the opening in the outer forward casing portion and supported from the inner reflecting casing side portions, tab slots-in, said inner reflecting casing, side portions bracing means within the outer casing portions and above the top portion of said inner reflecting casing for connecting the turned side portions of the outer rearward and forward casing portions and having end portions with slots therein, said foldable tabs on said forward and rearward casing portions projected through said slots in said reflector casing and through said slots in said bracing meansand folded thereby rigidly fastening said outer casing portions together and providing suspension means for holding the reflecting casing portions in place, atop portion having downwardly turned edges adapted to engage said outer rearward and outer forward casingportions and constrain them together toward said bracing means, means to attach said top portion to said bracing means, and electric heating means positioned withinsaid outer casing portions in heat reflecting relation to said reflecting casing portions to heat air and cause it to pass out of said heated air opening.

WILLIAM A. BARNES. 

